Preheater for reverberatory melting furnaces

Abstract

An improved preheater is provided suitable for use with gas or oil fired reverberatory melting furnaces for recycling aluminum scrap and other scrap metals. The improved preheater comprises a charge box having a bottom, and a chamber having a bed. The chamber is in communication with the charge box at one end, and, an exit at the other. A pusher is provided for pushing the contents of the charge box into the chamber and thus pushing the contents of the chamber towards the exit. The chamber is of uniform expanding dimensions from its one end in communication with the charge box towards the exit. The bed of the chamber carries openings therethrough from a gas chamber therebelow into which heated waste gas is passed for circulation through the openings in the bed through the contents of the chamber.

The embodiments of the invention in which an exclusive privilege or property is claimed are as follows: 
     
       1. An improved preheater suitable for processing large pieces of scrap metal prior to being charged into a reverberatory furnace, the preheater comprising a charge box having a bottom for receiving scrap metal, a chamber having a bed, the chamber in communication with the charge box at one end and an exit at the other, a pusher for pushing the contents of the charge box into the chamber and thus pushing the contents of the chamber towards the exit, the chamber of uniform expanding dimensions from its one end in communication with the charge box towards the exit so as to permit the pushing of the scrap metal in the one direction away from the charge box to the exit without undue compression of the scrap metal or jamming of the scrap metal in the chamber, the bed having a plurality of openings therethrough for passing heated gases into the chamber for preheating the scrap and the bed being oriented from the charge box to the exit in a fixed position selected from a range of fixed positions between being fixed and being inclined slightly upwardly from the charge box to the exit to being fixed and being inclined slightly downwardly from the charge box to the exit and when the bed is fixed and inclined slightly downwardly from the charge box to the exit, the bed carries a drain between the charge box and exit proximate the exit for draining any water falling from the scrap to the bed from the chamber. 
     
     
       2. The preheater of claim 1, wherein the preheater is in communication with a gas fired reverberatory furnace and waste gases generated thereby are fed through the openings in the bed to circulate through the scrap metal. 
     
     
       3. The preheater of claim 2, wherein the chamber is rectangular in cross-section and uniformly expands in both height and width from the opening at the one end of the chamber in communication with the charge box, to the exit. 
     
     
       4. The preheater of claim 3, wherein the bed comprises a plurality of laterally extending plates, one in front of another, each plate having a front edge closer the exit and a rear edge closer the charge box, the front edge of the plate immediately behind the plate closer the exit, overlying the rear edge of the plate closer the exit and vertically spaced therefrom to provide a plurality of laterally extending openings through the bed. 
     
     
       5. The preheater of claim 2, wherein the bed comprises a plurality of laterally extending plates, one in front of another, each plate having a front edge closer the exit and a rear edge closer the charge box, the front edge of the plate immediately behind the plate closer the exit, overlying the rear edge of the plate closer the exit and vertically spaced therefrom to provide a plurality of laterally extending openings through the bed. 
     
     
       6. The preheater of claim 2, wherein the waste gases are injected through openings through the bed, and a gas chamber is provided below the bed for receiving the heated gases prior to their passage through the openings. 
     
     
       7. The preheater of claim 1, wherein the chamber is rectangular in cross-section and uniformly expands in both height and width from the opening at the one end of the chamber in communication with the charge box, to the exit. 
     
     
       8. The preheater of claim 7, wherein the bed comprises a plurality of laterally extending plates, one in front of another, each plate having a front edge closer the exit and a rear edge closer the charge box, the front edge of the plate immediately behind the plate closer the exit, overlying the rear edge of the plate closer the exit and vertically spaced therefrom to provide a plurality of laterally extending openings through the bed. 
     
     
       9. The preheater of claim 1, wherein the bed comprises a plurality of laterally extending plates, one in front of another, each plate having a front edge closer the exit and a rear edge closer the charge box, the front edge of the plate immediately behind the plate closer the exit, overlying the rear edge of the plate closer the exit and vertically spaced therefrom to provide a plurality of laterally extending openings through the bed.